62 MIDDLESEX FLORA. 



CASSANDRA, Don. 



C. calyculata, Don. LEATHER-LEAF. 

 Common. April-May. 



ANDROMEDA, L. 

 A. polifolia, L. 



Tewksbury, Dracut, Reading, Concord, Littleton, et al. Not com- 

 mon. June. 

 A. ligustrina, Muhl. 

 Common. June-July. 



CLETHRA, L. 



C. alnifolia, L. WHITE ALDER. SWEET PEPPERBUSH. 

 Common. July-Aug. 



CALLUNA, Salisb. 



C. vulgaris, Salisb. HEATHER. 



This rare plant was discovered for the first time upon the American 

 mainland, by Jackson Dawson, in July, 1861, on low grounds in 

 Tewksbury. A second station has since been found in W. Andover, 

 Essex Co., five miles from the Tewksbury locality, of the "green 

 and smoothish variety precisely like the Tewksbury plant," Gray. 

 Subsequent discoveries of the Calluna at many different points 

 northward favor the conclusion that it is really indigenous hi 

 America. Mr. Dawson states that the Tewksbury station, never a 

 large one, is decreasing in area, partly from the inroads of botan- 

 ists, and partly from the encroachments of the woods beneath the 

 shade of which the heather almost always disappears. The for- 

 bearance of collectors with the timely removal of a few shrubs 

 would undoubtedly preserve this interesting survival of a former 

 flora. July-Aug. 



KALMIA, L. 



K. latifolia, L. MOUNTAIN LAUREL. 



Common in the northern towns, but rare elsewhere. June. 

 K. angustifolia, L. SHEEP LAUREL. LAMBKILL. 



Common. June. 

 K. glauca, Ait. PALE LAUREL. 



Ashby and Littleton (L. L. Dame) ; Westf ord (Misses Fletcher and 



Hodgman) ; Concord (G. E. Davenport) ; Natick (Austin Bacon) ; 



Groton and Carlisle (C. W. Jenks) ; Acton (Walter Deane). May. 



RHODODENDRON, L. 



R. viscosum, Torr. (Azalea viscosa, L., Man.) WHITE SWAMP 

 HONEYSUCKLE. SWAMP PINK. 

 Common. June-July. 



